Description: Es werden die Daten des Polarfront-Programms während des Internationalen Geophysikalischen Jahres 1957/58 verwendet, um die Frage des Eindringens jahresperiodischer Oberflächenstörungen zu untersuchen. Nach der Diskussion der Oberflächenstörungen und der bei der Ermittlung der Eindringtiefe auftretenden Fehler werden durch den Vergleich von TS-Kurven die gesuchten Tiefenwerte gefunden. Für das Seegebiet südöstlich Grönlands wird eine spezielle Untersuchung durchgeführt. Unter stark vereinfachten Verhältnissen werden vertikale Austauschkoeffizienten ermittelt. Zum Abschluß wird die Frage untersucht, wieweit die für das Jahr 1958 gefundenen Verhältnisse repräsentativ für das Untersuchungsgebiet sind. Data of the "Polar Front Survey", one of the most extensive oceanographic programs during the International Geophysical Year 1957/58, were used to determine the maximum depth of penetration of seasonal surface disturbances. The area of investigation covers the North Atlantic between 40°N-65°N and 10°W-45°W. It is established, that next to the annual water budget and the annual cycle of windspeed, the heat budget is the most important factor causing variations of yearly periods in deeper layers. The maximum depth of penetration is determined by comparing temperature - salinity curves both from spring and from autumn, which are obtained by means of a suitable averaging process (see plate 8, 9). The resulting depths reach from less than 200 m in the southern part of the area to more than 600 m west of Scotland and south of Iceland (see plate 10, fig. 20). The mean error of these depths was found to be about 15%, The weak haline stratification in the area southeast of Greenland gives rise to the sinking of cooled surface water in winter. Therefore extreme depths of more than 2000 m may be reached by annual surface disturbances (see plate 11). This area is well known as one of the sources of North Atlantic deep water. By means of strong simplifications vertical exchange coefficients were estimated (see table 2 and 3).

Description: Measuring temperature and salinity profiles in the world's oceans is crucial to understanding ocean dynamics and its influence on the heat budget, the water cycle, the marine environment and on our climate. Since 1983 the German research vessel and icebreaker Polarstern has been the platform of numerous CTD (conductivity, temperature, depth instrument) deployments in the Arctic and the Antarctic. We report on a unique data collection spanning 33 years of polar CTD data. In total 131 data sets (1 data set per cruise leg) containing data from 10 063 CTD casts are now freely available at doi:10.1594/PANGAEA.860066. During this long period five CTD types with different characteristics and accuracies have been used. Therefore the instruments and processing procedures (sensor calibration, data validation, etc.) are described in detail. This compilation is special not only with regard to the quantity but also the quality of the data – the latter indicated for each data set using defined quality codes. The complete data collection includes a number of repeated sections for which the quality code can be used to investigate and evaluate long-term changes. Beginning with 2010, the salinity measurements presented here are of the highest quality possible in this field owing to the introduction of the OPTIMARE Precision Salinometer.